1. Field of the invention
The present invention concerns a connector for a card containing an electronic circuit and in particular a smart card connector. A smart card is a card incorporating at least one electronic component with which electrical connections must be established in a card reader fitted to a taxiphone or a machine in a bank, for example.
2. Description of the prior art
The present invention is more particularly concerned with a connector for smart cards which are smaller (15.times.25 mm) than the familiar standard smart card (54.times.85 mm). Referred to hereinafter as "minicards", these cards comprise the same circuitry and the same connection system as standard cards. They are for use in portable radiotelephones, for example. They are designed to be used in portable radiotelephones to identify the owner or the renter of a unit, together with other functions. As a general rule, the minicard must be inserted into the connector by qualified personnel, rather than by the end user as is the case with the standard cards, and they must remain inside the unit for some time.
In prior art connectors for standard cards the card is inserted through a slot in the front of the unit. These connectors are described in U.S. Pat. No. 4 743 746, for example. They incorporate a guide casing into which the card is inserted through a front slot in a position slightly inclined relative to a median plane of the connector. The card is then moved into the read position in which contact is established with the electrical circuitry of the unit in which the connector is installed.
In this type of connector a free space must be provided in front of the entry slot sufficiently large to admit the card itself and the fingers of the person inserting the card. This criterion is very difficult to comply with in the case of minicards designed to be inserted into small, typically "pocket-size" units which are required to be of minimum size.
Also, the use of a guide casing increases the thickness of the connector. This is also a problem with minicards for portable units. Some applications require a maximum connector thickness of 3 mm, for example, and the guide casing already has a thickness of around 2 mm.
Furthermore, the usual applications of slotted units do not require absolute protection against possible movement of the card due to impact or vibration because the slotted units are usually installed on a fixed base. Also, in this type of unit the user has access to the card and can therefore re-insert it if it is inserted incorrectly. "Pocket" units, on the other hand, are designed to be carried around and are subjected to considerable movement, and the user must not have access to the minicard as would be required in order to reinsert it. There would therefore be little advantage in employing the connectors used in slotted units for applications using minicards.
Finally, when the card is inserted into the casing the circuitry carried by the card may rub against the inside wall of the casing. This may damage the circuitry of the card.
One object of the present invention is therefore to provide a connector for a card containing an electronic circuit of minimum overall dimensions which holds the card securely.
Another object of the present invention is to provide a connector for a card containing an electronic circuit meeting requirements for use in compact "pocket" units.